Amygdalin Improves Allergic Asthma via the Thymic Stromal Lymphopoietin-dendritic Cell-OX40 Ligand Axis in a Mouse Model

Asthma, characterized by persistent inflammation and increased sensitivity of the airway, is the most common chronic condition among children. Novel, safe, and reliable treatment strategies are the focus of current research on pediatric asthma. Amygdalin, mainly present in bitter almonds, has anti-inflammatory and immunoregulatory potential, but its effect on asthma remains uninvestigated. Here, the impact of amygdalin on the thymic stromal lymphopoietin (TSLP)-dendritic cell (DC)-OX40L axis was investigated. A BALB/c mouse model for allergic asthma was established using the ovalbumin-sensitization method. Amygdalin treatment was administered between days 21 and 27 of the protocol. Cell numbers and hematoxylin and eosin (H&E) staining in bronchoalveolar lavage fluid (BALF) were used to observe the impact of amygdalin on airway inflammation. TSLP, IL-4, IL-5, IL-13, and IFN-γ concentrations were determined via Enzyme-linked immunosorbent assay (ELISA). TSLP, GATA-3, and T-bet proteins were measured using western blotting. Cell-surface receptor expression on DCs (MHC II, CD80, and CD86) was assessed via flow cytometry. OX40L mRNA and protein levels were detected using western blotting and qRT-PCR, respectively. Amygdalin treatment attenuated airway inflammation decreased BALF TSLP levels, inhibited DC maturation, restrained TSLP-induced DC surface marker expression (MHCII, CD80, and CD86), and further decreased OX40L levels in activated DCs. This occurred together with decreased Th2 cytokine levels (IL-4, IL-5, and IL-13) and GATA3 expression, whereas Th1 cytokine (IFN-γ) levels and T-bet expression increased. Amygdalin thus regulates the Th1/Th2 balance through the TSLP-DC-OX40L axis to participate in inflammation development in the airways, providing a basis for potential allergic asthma treatments.

Amygdalin alleviated TGF-β-induced epithelial-mesenchymal transition in bronchial epithelial cells

OBJECTIVE

Transforming growth factor-beta TGF-β-induced epithelial-mesenchymal transition (EMT) in bronchial epithelial cells contributes to airway wall remodeling in asthma. This study aims to explore the role of amygdalin, an active ingredient in bitter almonds, in TGF-β-induced EMT in bronchial epithelial cells and to elucidate the possible mechanisms underlying its biological effects.

METHODS

An asthmatic mouse model was established through ovalbumin induction. Primary mouse bronchial epithelial cells and a human bronchial epithelial cell line were incubated with transforming growth factor-beta (TGF-β) to induce EMT, whose phenotype of cells was evaluated by the expressions of EMT markers [alpha-smooth muscle actin (α-SMA), vimentin, and fibronectin] and cell migration capacity. A co-immunoprecipitation assay was performed to assess the ubiquitination of heparanase (HPSE).

RESULTS

In asthmatic model mice, amygdalin treatment relieved airway wall remodeling and decreased expressions of EMT markers (α-SMA and vimentin). In TGF-β-treated bronchial epithelial cells, amygdalin treatment decreased the mRNA and protein levels of EMT markers (α-SMA, vimentin, and fibronectin) without impairing cell viability. Through the Swiss Target Prediction database, HPSE was screened as a candidate downstream target for amygdalin. HPSE overexpression further promoted TGF-β-induced EMT while the HPSE inhibitor suppressed TGF-β-induced EMT in bronchial epithelial cells. In addition, HPSE overexpression reversed the inhibitory effect of amygdalin on TGF-β-induced EMT in bronchial epithelial cells. The following mechanism exploration revealed that amygdalin downregulated HPSE expression by enhancing ubiquitination.

CONCLUSION

Our study showed that amygdalin inhibited TGF-β-induced EMT in bronchial epithelial cells and found that the anti-EMT activity of amygdalin might be related to its regulatory effect on HPSE expression.

Amygdalin: A Review on Its Characteristics, Antioxidant Potential, Gastrointestinal Microbiota Intervention, Anticancer Therapeutic and Mechanisms, Toxicity, and Encapsulation

Bioactive amygdalin, found in high concentrations in bitter almonds, has been recognized as a symbol of the cyanogenic glycoside chemical organic substance, which was initially developed as a pharmaceutical for treating cancer after being hydrolyzed to hydrogen cyanide (HCN). Regrettably, research has shown that HCN can also damage normal cells, rendering it non-toxic to the human body. Extreme controversy surrounds both in vivo and in vitro studies, making its use risky. This review provides an extensive update on characteristics, antioxidant potential, gastrointestinal microbiota intervention, anticancer therapeutic, mechanisms, toxicity, and encapsulation of amygdalin. Antioxidant, anti-tumor, anti-fibrotic, antiatherosclerosis, anti-inflammatory, immunomodulatory, and analgesic characteristics, and the ability to improve digestive and reproductive systems, neurodegeneration, and cardiac hypertrophy are just some of the benefits of amygdalin. Studies verified the HCN-produced amygdalin to be harmful orally, but only at very high doses. Although intravenous treatment was less effective than the oral method, the oral route has a dose range of 0.6 to 1 g daily. Amygdalin’s toxicity depends heavily on the variety of bacteria in the digestive tract. Unfortunately, there is currently no foolproof method for determining the microbial consortium and providing a safe oral dosage for every patient. Amygdalin encapsulation in alginate-chitosan nanoparticles (ACNPs) is a relatively new area of research. Amygdalin has an enhanced cytotoxic effect on malignant cells, and ACNPs can be employed as an active drug-delivery system to release this compound in a regulated, sustained manner without causing any harm to healthy cells or tissues. In conclusion, a large area of research for a substance that might be the next step in cancer therapy is opened up due to unverified and conflicting data.

In Vivo Growth Inhibition of Human Caucasian Prostate Adenocarcinoma in Nude Mice Induced by Amygdalin with Metabolic Enzyme Combinations

Cancer of the prostate is an indicated type that is often recorded as a kind of cancer in men and the second critical cause of mortality through cancer cases. Many pharmacological investigations have shown that numerous herbal substances possess anticancer action. Amygdalin (AMD) has antitumour capabilities and works as an antioxidant, antibacterial, anti-inflammatory, and immune-regulating characteristics. The anticancer effects of amygdalin and its metabolizing enzymes, rhodanese (RHD) and betaglucosidase (BGD), were examined in vivo, as well as their antitumour processes. Novel, effective combination agents are necessary to increase existing cancer treatment rates. This research was aimed at determining the anticarcinogenic impact of amygdalin (AMD) in vivo. This research was aimed at determining the RHD and BGD on the anticarcinogenic impact of AMD in vivo. Subcutaneously, PC3 prostate cancer cell lines were implanted into nude mice. Mice were treated every day with 0.5 ml of 50 mg/ml (AMD), AMD+ (RHD 0.1 mg/ml), AMD+(BGD 0.1 mg/ml), and doxorubicin (DOX 50 mg/ml). Mice were normalized for negative control with untreated mice. In in vivo, morphopathological alterations in the tumour tissue were analyzed by histopathological staining methods. After 35 days of therapy, tumour growth and size inhibition were evident, indicating a function for the metabolic enzymes BGD and RHD in regulating AMD's anticancer effect in vivo. We concluded the critical role of metabolic enzymes BGD and RHD in elevating the antigrowth of PC3 cancer cell lines in Balb/c nude mice treated with AMD.

Amygdalin Ameliorates Liver Fibrosis through Inhibiting Activation of TGF-β/Smad Signaling

OBJECTIVE

To observe the effect of amygdalin on liver fibrosis in a liver fibrosis mouse model, and the underlying mechanisms were partly dissected in vivo and in vitro.

METHODS

Thirty-two male mice were randomly divided into 4 groups, including control, model, low- and high-dose amygdalin-treated groups, 8 mice in each group. Except the control group, mice in the other groups were injected intraperitoneally with 10% carbon tetrachloride (CCl₄)-olive oil solution 3 times a week for 6 weeks to induce liver fibrosis. At the first 3 weeks, amygdalin (1.35 and 2.7 mg/kg body weight) were administered by gavage once a day. Mice in the control group received equal quantities of subcutaneous olive oil and intragastric water from the fourth week. At the end of 6 weeks, liver tissue samples were harvested to detect the content of hydroxyproline (Hyp). Hematoxylin and eosin and Sirius red staining were used to observe the inflammation and fibrosis of liver tissue. The expressions of collagen I (Col-I), alpha-smooth muscle actin (α-SMA), CD31 and transforming growth factor β (TGF-β)/Smad signaling pathway were observed by immunohistochemistry, quantitative real-time polymerase chain reaction and Western blot, respectively. The activation models of hepatic stellate cells, JS-1 and LX-2 cells induced by TGF-β1 were used in vitro with or without different concentrations of amygdalin (0.1, 1, 10 µmol/L). LSECs. The effect of different concentrations of amygdalin on the expressions of liver sinusoidal endothelial cells (LSECs) dedifferentiation markers CD31 and CD44 were observed.

RESULTS

High-dose of amygdalin significantly reduced the Hyp content and percentage of collagen positive area, and decreased the mRNA and protein expressions of Col-I, α-SMA, CD31 and p-Smad2/3 in liver tissues of mice compared to the model group (P<0.01). Amygdalin down-regulated the expressions of Col-I and α-SMA in JS-1 and LX-2 cells, and TGFβ R1, TGFβ R2 and p-Smad2/3 in LX-2 cells compared to the model group (P<0.05 or P<0.01). Moreover, 1 and 10 µmol/L amygdalin inhibited the mRNA and protein expressions of CD31 in LSECs and increased CD44 expression compared to the model group (P<0.05 or P<0.01).

CONCLUSIONS

Amygdalin can dramatically alleviate liver fibrosis induced by CCl₄ in mice and inhibit TGF-β/Smad signaling pathway, consequently suppressing HSCs activation and LSECs dedifferentiation to improve angiogenesis.

Amygdalin - A pharmacological and toxicological review

ETHNOPHARMACOLOGICAL RELEVANCE

Amygdalin is commonly distributed in plants of the Rosaceae, such as peach, plum, loquat, apple and bayberry, but most notably in the seeds (kernels) of apricot almonds. As a naturally aromatic cyanogenic compound, it has long been used in Asia, Europe and other regions for the treatment of various diseases including cough, asthma, nausea, leprosy and leukoderma. Importantly, in recent years, an increasing attention has been paid to its antitumor effect.

AIM OF THE STUDY

The paper aims to review the pharmacological activities and toxicological effects of amygdalin and provide a reference and perspective for its further investigation.

METHODS

Electronic databases including the Web of Science, Cochrane Library, PubMed, EMBASE, the Chinese Biological Medicine Database, China National Knowledge Infrastructure, Wanfang database and VIP information database were searched up to November 2019 to identify eligible studies. A meticulous review was performed, an in-depth analysis on the pharmacological activity and toxicology of amygdalin was conducted, and perspectives for future research were also discussed.

RESULTS

A total of 110 papers about in vitro/in vivo studies on amygdalin have been reviewed. Analysis on the data suggested that this compound presented pharmacological activities of anti-tumor, anti-fibrotic, anti-inflammatory, analgesic, immunomodulatory, anti-atherosclerosis, ameliorating digestive system and reproductive system, improving neurodegeneration and myocardial hypertrophy, as well as reducing blood glucose. In addition, studies revealed that amygdalin's toxicity was caused by its poisonous decomposite product of benzaldehyde and hydrogen cyanide after oral ingestion, toxicity of intravenous administration route was far less than the oral route, and it can be avoidable with an oral dose ranging from 0.6 to 1 g per day.

CONCLUSION

This paper has systematically reviewed the pharmacology and toxicology of amygdalin and provided comprehensive information on this compound. We hope this review highlights some perspectives for the future research and development of amygdalin.

Ameliorative effects of vitamin B17 on the kidney against Ehrlich ascites carcinoma induced renal toxicity in mice

Cancer is the major cause of death and many factors that lead to its occurrences, such as environmental pollution and pesticides and other factors. Ehrlich carcinoma development depends on many things associated with the environment, nutrition, personal habits, and family history. The present study aimed to evaluate the potential protective effects of vitamin B17 (VB17) against Ehrlich ascites carcinoma (EAC) that induced kidney toxicity in female mice. The mice were divided into five groups (first group, control group; second group, VB17 group; third group, EAC group; fourth group, pretreated EAC with VB17; fifth group, cotreated EAC with VB17). Results showed the VB17 in pretreated (G4) and cotreated (G5) groups lead to an improvement in DNA damage and cytological examination, in addition significantly (P < .05) increase in Na⁺ , red blood cell, hemoglobin, hematocrit value, mean corpuscular hemoglobin (MCH), and MCH concentration, whereas significantly (P < .05) decrease in urea, creatinine, K⁺ , platelets, and white blood cells while insignificant (P < .05) changes in mean corpuscular volume when compared to the EAC group. Many histopathological changes were observed in kidney sections in EAC as marked damage and degenerated, glomerular atrophy, the Malpighian corpuscles that lost their characteristic configuration. On the other hand, a moderate improvement and arrangement in the kidney histological structure in pretreated VB17 + EAC, while a mild enhancement and arrangement of the kidney structure in cotreated EAC + VB17. In addition, depletion in renal P53 and PCNA protein expression compared with the EAC group. It could be concluded that VB17 has a potential renal protective effect against EAC cells induced kidney injury.

Chinese medicine CGA formula ameliorates liver fibrosis induced by carbon tetrachloride involving inhibition of hepatic apoptosis in rats

ETHNOPHARMACOLOGICAL REVELVANCE

CGA consisting of Cordyceps sinensis mycelia polysaccharide, gypenosides and amygdalin, was demonstrated to be the effective components formula in Fuzheng Huayu (FZHY) capsule, a traditional Chinese medicine approved by China food and drug administration for treatment of liver fibrosis and to inhibit transforming growth factor-β1 (TGF-β1) signaling, previously.

AIM OF THE STUDY

To evaluate the effects of CGA on hepatic apoptosis in liver fibrosis induced by carbon tetrachloride (CCl₄).

MATERIALS AND METHODS

The hepatic injury and histology was detected by serum biomarker assay and hematoxylin-eosin staining. The hepatic collagen was illustrated by Sirius red staining and hydroxyproline (Hyp) concentration. The hepatic stellate cells (HSCs) activation and hepatic apoptosis was visualized by immunohistochemical analysis of α-smooth muscle actin (α-SMA) and terminal deoxynucleotidyl transferase-mediated dUPT nick-end labeling (TUNEL) assay respectively. The protein expression of collagen type I (Col-I), α-SMA, TGF-β1, Fas, tumor necrosis factor receptor 1 (TNF-R1), cleaved-caspase-8, cleaved-caspase-10, cleaved-caspase-9, cleaved-caspase-3, mitochondrial Bcl-2, Bcl-2 associated X protein (Bax), Bcl-2 homologous antagonist/killer (Bak), cytochrome C and cytoplasmic cytochrome C was detected by western-blot.

RESULTS

CGA or FZHY ameliorated liver histological changes, decreasing serum alanine aminotransferase, aspartate aminotransferase, hepatic Hyp, TUNEL positive-stained area, and down-regulated the protein expression of α-SMA, TGF-β1, Col-I, Fas, TNF-R1, cleaved-caspase-8, cleaved-caspase-10, cleaved-caspase-9, and cleaved-caspase-3, mitochondrial Bax, Bak, and cytoplasmic cytochrome C, while restored the expression of mitochondrial Bcl-2 and cytochrome C.

CONCLUSION

CGA formula ameliorates liver fibrosis induced by CCl₄, which is correlated to its inhibition on hepatic apoptosis.

Amygdalin attenuates acute liver injury induced by D-galactosamine and lipopolysaccharide by regulating the NLRP3, NF-κB and Nrf2/NQO1 signalling pathways

Acute liver injury (ALI) is a life-threatening syndrome accompanied by overwhelming inflammation. Amygdalin (AGD) has been reported to possess various biological activities, particularly anti-inflammatory activity. The current study was designed to assess the protective effects and underlying mechanisms of AGD against ALI induced by d-galactosamine (GalN) and lipopolysaccharide (LPS) in mice. The results indicated that AGD treatment effectively reduced the lethality, ameliorated the histopathological liver changes, reduced the malondialdehyde (MDA) and myeloperoxidase (MPO) levels, and decreased the alanine transaminase (ALT) and aspartate aminotransferase (AST) levels resulting from LPS/GalN challenge. Moreover, AGD significantly inhibited LPS/GalN-induced inflammatory responses in mice with ALI by reducing not only the secretion of tumour necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 but also the protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Additionally, our results demonstrated that the inhibitory effect of AGD was due to the suppressed activation of nuclear factor-kappa B (NF-κB) and nucleotide-binding domain (NOD-)like receptor protein 3 (NLRP3) inflammasome activity. Furthermore, AGD treatment substantially increased nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear translocation and enhanced NAD (P) H: quinoneoxidoreductase 1 protein expression, which was reversed by a Nrf2 inhibitor, in HepG2 cells. In summary, our investigations suggested that the ability of AGD to ameliorate LPS/GalN-induced ALI may involve the inhibition of the NLRP3 inflammasome and NF-κB signalling pathways and the upregulation of the Nrf2/NQO1 signalling pathway.

Amygdalin improves microcirculatory disturbance and attenuates pancreatic fibrosis by regulating the expression of endothelin-1 and calcitonin gene-related peptide in rats

BACKGROUND

The pathogenesis of chronic pancreatitis (CP) is a complex process of interaction between tissue injury and repair, which involves microcirculatory disturbance. Amygdalin, an effective component extracted from Semen Persicae (a kind of Chinese herbal medicine), can decrease blood viscosity and improve microcirculation. In this study, we investigated the therapeutic effects of amygdalin on pancreatic fibrosis in rats with CP.

METHODS

The rat CP model was induced by injecting dibutyltin dichloride (DBTC) into the right caudal vein. Amygdalin was administrated via the penile vein at a dose of 10 mg/(kg d) from the next day, after the induction of CP, once a day for the previous 3 days, and then once every 2 days, until the end of the experiment. Body weight was observed every 7 days. Pancreatic blood flow and histopathological changes were assessed at 28 days. The activation of pancreatic stellate cells (PSCs) was estimated by the expression of α-smooth muscle actin (α-SMA). At the same time, the expression of platelet-derived growth factor-BB (PDGF-BB), transforming growth factor β-1 (TGFβ-1), endothelin-1 (ET-1), and calcitonin gene-related peptide (CGRP) of pancreatic tissues were detected.

RESULTS

Treatment of CP rats with amygdalin improved body weight and pancreatic blood flow, as well as alleviated pancreatic fibrosis and acinar destruction, accompanied by the down-regulation of the expressions of α-SMA, PDGF-BB, TGFβ-1, and ET-1, and the up-regulation of the CGRP's expression.

CONCLUSION

Amygdalin could reduce the production of pro-fibrotic cytokines, inhibit the activation of PSCs, and attenuate pancreatic fibrosis in a rat with CP. The mechanism probably includes improving microcirculatory disturbance by regulating the production of ET-1 and CGRP.

Protective Effect of Amygdalin on LPS-Induced Acute Lung Injury by Inhibiting NF-κB and NLRP3 Signaling Pathways

The acute lung injury (ALI) is a leading cause of morbidity and mortality in critically ill patients. Amygdalin is derived from the bitter apricot kernel, an efficacious Chinese herbal medicine. Although amygdalin is used by many cancer patients as an antitumor agent, there is no report about the effect of amygdalin on acute lung injury. Here we explored the protective effect of amygdalin on ALI using lipopolysaccharide (LPS)-induced murine model by detecting the lung wet/dry ratio, the myeloperoxidase (MPO) in lung tissues, inflammatory cells in the bronchoalveolar lavage fluid (BALF), inflammatory cytokines production, as well as NLRP3 and NF-κB signaling pathways. The results showed that amygdalin significantly reduced LPS-induced infiltration of inflammatory cells and the production of TNF-α, IL-1β, and IL-6 in the BALF. The activity of MPO and lung wet/dry ratio were also attenuated by amygdalin. Furthermore, the western blotting analysis showed that amygdalin remarkably inhibited LPS-induced NF-κB and NLRP3 activation. These findings indicate that amygdalin has a protective effect on LPS-induced ALI in mice. The mechanism may be related to the inhibition of NF-κB and NLRP3 signaling pathways.

Amygdalin, quackery or cure?

BACKGROUND

The cyanogenic diglucoside, amygdalin, has gained high popularity among cancer patients together with, or in place of, conventional therapy. Still, evidence based research on amygdalin is sparse and its benefit controversial.

PURPOSE

Since so many cancer patients consume amygdalin, and many clinicians administer it without clear knowledge of its mode of action, current knowledge has been summarized and the pros and cons of its use weighed.

METHODS

A retrospective analysis was conducted for amygdalin relevant reports using the PubMed database with the main search term "Amygdalin" or "laetrile", at times combined with "cancer", "patient", "cyanide" or "toxic". We did not exclude any "unwanted" articles. Additionally, internet sources authorized by governmental or national institutions have also been included.

SECTIONS

Individual chapters summarize pharmacokinetics, preclinical and clinical studies and toxicity.

CONCLUSION

No convincing evidence showing that amygdalin induces rapid, distinct tumor regression in cancer patients, particularly in those with late-stage disease, is apparent. However, there is also no evidence that purified amygdalin, administered in "therapeutic" dosage, causes toxicity. Multiple aspects of amygdalin administration have not yet been adequately explored, making further investigation necessary to evaluate its actual therapeutic potential.

[Amygdalin - structure and clinical significance]

In this publication we described amygdalin. It was isolated for the first time in the 19th century. Amygdalin is called interchangeably vitamin B17 or laetrile. Since more than a hundred years, there has been reports about its unique anticancer properties. We tried to introduce the present knowledge about therapeutic efficacy of laetrile. Most of these studies has been made in the in vitro environment. The lack of appropriate studies forced scientists to examine the positive influence of amygdalin on many diseases like: bladder cancer, prostate cancer, cervical cancer, colon cancer, promyelocytic leukemia, chronic kidney disease, psoriasis and other.

Laetrile treatment for cancer

BACKGROUND

Laetrile is the name for a semi-synthetic compound which is chemically related to amygdalin, a cyanogenic glycoside from the kernels of apricots and various other species of the genus Prunus. Laetrile and amygdalin are promoted under various names for the treatment of cancer although there is no evidence for its efficacy. Due to possible cyanide poisoning, laetrile can be dangerous.

OBJECTIVES

To assess the alleged anti-cancer effect and possible adverse effects of laetrile and amygdalin.

SEARCH METHODS

We searched the following databases: CENTRAL (2014, Issue 9); MEDLINE (1951-2014); EMBASE (1980-2014); AMED; Scirus; CINAHL (all from 1982-2015); CAMbase (from 1998-2015); the MetaRegister; the National Research Register; and our own files. We examined reference lists of included studies and review articles and we contacted experts in the field for knowledge of additional studies. We did not impose any restrictions of timer or language.

SELECTION CRITERIA

Randomized controlled trials (RCTs) and quasi-RCTs.

DATA COLLECTION AND ANALYSIS

We searched eight databases and two registers for studies testing laetrile or amygdalin for the treatment of cancer. Two review authors screened and assessed articles for inclusion criteria.

MAIN RESULTS

We located over 200 references, 63 were evaluated in the original review, 6 in the 2011 and none in this update. However, we did not identify any studies that met our inclusion criteria.

AUTHORS' CONCLUSIONS

The claims that laetrile or amygdalin have beneficial effects for cancer patients are not currently supported by sound clinical data. There is a considerable risk of serious adverse effects from cyanide poisoning after laetrile or amygdalin, especially after oral ingestion. The risk-benefit balance of laetrile or amygdalin as a treatment for cancer is therefore unambiguously negative.

Laetrile treatment for cancer

BACKGROUND

Laetrile is the name for a semi-synthetic compound which is chemically related to amygdalin, a cyanogenic glycoside from the kernels of apricots and various other species of the genus Prunus. Laetrile and amygdalin are promoted under various names for the treatment of cancer although there is no evidence for its efficacy. Due to possible cyanide poisoning, laetrile can be dangerous.

OBJECTIVES

To assess the alleged anti-cancer effect and possible adverse effects of laetrile and amygdalin.

SEARCH METHODS

We searched the following databases: CENTRAL (2011, Issue 1); MEDLINE (1951-2011); EMBASE (1980-2011); AMED; Scirus; CancerLit; CINAHL (all from 1982-2011); CAMbase (from 1998-2011); the MetaRegister; the National Research Register; and our own files. We examined reference lists of included studies and review articles and we contacted experts in the field for knowledge of additional studies. We did not impose any restrictions of timer or language.

SELECTION CRITERIA

Randomized controlled trials (RCTs) and quasi-RCTs.

DATA COLLECTION AND ANALYSIS

We searched eight databases and two registers for studies testing laetrile or amygdalin for the treatment of cancer. Two review authors screened and assessed articles for inclusion criteria.

MAIN RESULTS

We located over 200 references, 63 were evaluated in the original review and an additional 6 in this update. However, we did not identify any studies that met our inclusion criteria.

AUTHORS' CONCLUSIONS

The claims that laetrile or amygdalin have beneficial effects for cancer patients are not currently supported by sound clinical data. There is a considerable risk of serious adverse effects from cyanide poisoning after laetrile or amygdalin, especially after oral ingestion. The risk-benefit balance of laetrile or amygdalin as a treatment for cancer is therefore unambiguously negative.

Laetrile for cancer: a systematic review of the clinical evidence

BACKGROUND

Many cancer patients treated with conventional therapies also try 'alternative' cancer treatments. Laetrile is one such 'alternative' that is claimed to be effective by many alternative therapists. Laetrile is also sometimes referred to as amygdalin, although the two are not the same.

OBJECTIVE

The aim of this review is to summarize all types of clinical data related to the effectiveness or safety of laetrile interventions as a treatment of any type of cancer.

MATERIALS AND METHODS

All types of clinical studies containing original clinical data of laetrile interventions were included. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (from 1951), EMBASE (from 1980), Allied and Complementary Medicine (AMED), Scirus, CancerLit, Cumulative Index to Nursing and Allied Health (CINAHL; all from 1982), CAMbase (from 1998), the MetaRegister, the National Research Register, and our own files. For reports on the safety of laetrile, we also searched the Uppsala database. No language restrictions were imposed.

RESULTS

Thirty six reports met our inclusion criteria. No controlled clinical trials were found. Three articles were nonconsecutive case series, 2 were consecutive case series, 6 were best case series, and 25 were case reports. None of these publications proved the effectiveness of laetrile.

CONCLUSION

Therefore, the claim that laetrile has beneficial effects for cancer patients is not supported by sound clinical data.

Laetrile treatment for cancer

BACKGROUND

Laetrile is an unconventional therapy which has been used illegally for decades by cancer patients who together with some alternative therapists claim its effectiveness as an anti-cancer treatment. It has been often referred to as amygdalin, although the two are not the same.

OBJECTIVES

The aim of this review was to assess the alleged anti-cancer effect and the possible harms of Laetrile as a sole or adjunctive therapy in cancer treatment.

SEARCH STRATEGY

We searched The Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE (from 1951); EMBASE (from 1980); Allied and Complementary Medicine (AMED), Scirus, CancerLit, CINAHL (all from 1982); CAMbase (from 1998); the MetaRegister; the National Research Register and our own files. No language restrictions were imposed.

SELECTION CRITERIA

Randomized clinical trials (RCTs) and non randomized controlled clinical trials (non-RCTs).

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trials for inclusion in the review, assessed study quality and extracted data.

MAIN RESULTS

No RCTs or non-RCTs were found, so no abstraction of outcome data could be performed in this systematic review

AUTHORS' CONCLUSIONS

The claim that Laetrile has beneficial effects for cancer patients is not supported by data from controlled clinical trials. This systematic review has clearly identified the need for randomised or controlled clinical trials assessing the effectiveness of Laetrile or amygdalin for cancer treatment.

Pharmacological properties of traditional medicines (XXVII). Interaction between Ephedra Herb and Gypsum under hyperthermal conditions in rats

There are many important considerations in the interactions among the herbal constituents in a prescription of traditional Chinese medicine (TCM). Ephedra Herb [Chinese characters: see text] (Eph) is described a warm and acrid agent in TCM. The combination of Eph and Gypsum [Chinese characters: see text] (Eph-Gyp) shows specific actions in patients with different body temperatures. Previous reports suggested that Gypsum prevents the thermogenesis effect induced by ephedrine at an ambient temperature of 22 degrees C. In this investigation, the properties of Eph-Gyp in hyperthermal rats were studied in detail. It was shown that Gypsum Extract (GyE) enhanced the thermogenesis of Eph in hyperthermal rats, although not in normal rats. The results support not only the opposite actions of Eph-GyE but also the clinical differences in the symptomatic patterns of body temperature for Makyo-Kanseki-To [Chinese characters: see text] and Dai-Seiryu-To [Chinese characters: see text].

[Analgesic effect and no physical dependence of amygdalin]

Analgesic effect of amygdalin (AM) in mice was observed in hot plate and acetic acid-induced writhing tests. AM did not induce tolerance as morphine did, and did not cause morphine-characteristic tail-erecting response in mice. Mice given AM and then challenged with nalorphine showed no jumping response. AM could not substitute for morphine in morphine-addicted rats in relieving withdrawal syndrome. No antiinflammatory activity was found with AM.

Court-ordered reimbursement for unproven medical technology. Circumventing technology assessment

OBJECTIVE--Because we found examples where courts of law ruled against insurance carriers that had been sued for reimbursement for unproven medical procedures, we conducted a case study to determine the reasoning behind these decisions that run counter to accepted medical science. Such actions circumvent health technology assessment and could contribute to escalating health care costs and poorer quality health care. DATA SOURCES--A literature search identified 17 cases between 1980 and 1989 in which an insurance company was sued to reimburse a patient who had received an unproven or questionable health technology; 14 of these suits were decided in favor of the plaintiff, and the insurance company was ordered to pay. Discussed in this article are six of these cases, two involving Laetrile (amygdalin), two involving immunoaugmentative therapy, and two involving thermography, technologies that had previously been assessed as not safe, not effective, or inadequately evaluated. DATA SYNTHESIS AND CONCLUSIONS--The circumstances determining how the courts arrive at these "unscientific" decisions fall into three general categories: (1) for legal reasons, the insurance contract is interpreted in favor of the insured; (2) the reluctance and/or inability, legal or otherwise, of the courts to use published scientific literature; and (3) the use of adversarial "expert" witnesses with potential conflicts of interest. To address this situation, we first urge the legal and insurance industries to cooperate in improving the contract language and process in a way that would be both legally and scientifically appropriate. Second, we encourage the courts to use and foster the use of published peer-reviewed scientific material as evidence whenever possible. Third, we recommend that the courts choose their own unbiased expert witnesses to interpret scientific material.

Unproven methods of cancer management. Laetrile

"Laetrile" is used interchangeably with "amygdalin" to designate natural substances, derived primarily from apricots and almonds, that can release cyanide, which is lethal to living organisms. In the 1920s, Dr. Ernst T. Krebs, Sr., formulated a theory that amygdalin could kill cancer cells. His theory was inconsistent with biochemical facts and has since been modified at least twice by his son, Ernst T. Krebs, Jr. Extensive work has been done by cancer scientists to test the claim that Laetrile fights cancer. Many animal experiments in the 1970s showed a complete lack of tumor killing by Laetrile. Reviews of the medical records of patients whose cancers were claimed to be reduced or cured after Laetrile treatment found insufficient medical evidence to judge Laetrile's efficacy. Finally, in a clinical trial in cancer patients reported in 1982, Laetrile neither caused shrinkage of tumors, nor increased survival time, nor alleviated cancer symptoms, nor enhanced well-being. Several reports in the medical literature document instances in which Laetrile has caused serious, life-threatening toxicity when taken in large doses in the manner prescribed by Laetrile advocates. In light of the lack of efficacy of Laetrile and its demonstrated ability to cause harm, Laetrile should not be used to treat cancer.

A clinical trial of amygdalin (Laetrile) in the treatment of human cancer

One hundred seventy-eight patients with cancer were treated with amygdalin (Laetrile) plus a "metabolic therapy" program consisting of diet, enzymes, and vitamins. The great majority of these patients were in good general condition before treatment. None was totally disabled or in preterminal condition. One third had not received any previous chemotherapy. The pharmaceutical preparations of amygdalin, the dosage, and the schedule were representative of past and present Laetrile practice. No substantive benefit was observed in terms of cure, improvement or stabilization of cancer, improvement of symptoms related to cancer, or extension of life span. The hazards of amygdalin therapy were evidenced in several patients by symptoms of cyanide toxicity or by blood cyanide levels approaching the lethal range. Patients exposed to this agent should be instructed about the danger of cyanide poisoning, and their blood cyanide levels should be carefully monitored. Amygdalin (Laetrile) is a toxic drug that is not effective as a cancer treatment.

Taking laetrile: conversion to medial deviance

For members of the CCS, laetrile use occurs in a self-help social context where users derive substantial social and emotional support from fellow members. We are convinced that much of the appeal of laetrile results from this social context in which it is frequently used. The CCS and the extensive network of similar organizations are fulfilling unmet needs in cancer patients and those fearful of cancer. Until conventional cancer therapy deals more successfully with the social and psychological needs of cancer patients, promoters of laetrile will till fertile ground.

Attitudes toward laetrile in relation to death anxiety and experience with cancer in the family

Three questionnaires concerning previous experiences and attitudes toward Laetrile were given to 68 college students and 44 professors. The hypothesis that individuals with greater anxiety would believe more strongly in the efficacy of Laetrile was supported. Positive attitudes toward Laetrile's effectiveness correlated significantly with higher death anxiety ( r = .25, p < .02), higher anxiety about cancer ( r = .25), and having a death from cancer in the extended family ( r = .26). None of these variables correlated significantly with attitudes toward Laetrile's legalization, a statistically independent measure.